Power tongs



March l, 1955 R. n. GARDNER POWER TONGS 5 She'etS-Sheet l Filed May 28, 1949 Y@ Nn m@ 5 Fzy March 1, 1955 R. l; GARDNER POWER TONGS 5 Sheets-Sheet 2 Filed May 28, 1949 ...LWTHHQQ March 1, 1955 R. l. GARDNER 2,703,221

POWER ToNGs.

Filed May 28, 1949 SSheets-Sheet 3 EL A @u Lil-25 7 March 1, 1955 Filed May 28,' 1949 R. l. GARDNER 2,703,221

POWER ToNGs 5 Sheets-Sheet 4 57 M5 A rra/@Mfrs March 1, 1955 R. l. GARDNER POWER TONGS 5 Sheets-Sheet 5 Filed May 28, 1949 United States Patent VO POWER TON GS Robert I. Gardner, Los Angeles, Calif., assignor to Hillman-Kelley, Los Angeles, Calif., a partnership comlosed of J. M. Hillman, J. Grover Kelley, and Markley Brown Application May 28, 1949, Serial No. 96,073

18 Claims. (Cl. Z55-35) My invention relates to a power tongs or wrench for use with such articles as pipes, rods, or the like, articles of this nature being referred to hereinafter as pipes for convenience.

In general, a power tongs of the type under consideration includes a housing comprising an annular stator having an annular rotor disposed therein, and includes a pipe-gripping structure carried by the rotor, a suitable power means for driving the rotor being carried by the housing. The pipe-gripping structure conventionally includes jaw means, which comprises at least two relatively movable jaws, for gripping a pipe to be rotated, and includes means for opening and closing the jaws so that the latter respectively disengage and engage the pipe. In order to permit lateral application of such a power tongs to the pipe, 'the rotor and stator are provided with,

registrable radial throats through which the pipe may be inserted into the interior of the rotor and into operative relation with the pipe-gripping structure. Such a power tongs is usually suspended in a manner to permit it to be swung into and out of operative relation with the pipe to be roated, although it will be understood that the power tongs may be mounted in other ways also.

A primary object of the invention is to provide an improved pipe-gripping structure for a power tongs of the foregoing general character.

Another object of the invention is to provide a power tongs having actuating means for opening and closing the jaws of the pipe-gripping structure automatically upon rotation of the rotor relative to the stator.

An important object of the invention is to provide a power tongs wherein the clamping force applied to the pipe as the jaws are closed by the jaw actuating means increases with increases in the torque applied to the rotor.

I prefer to accomplish the preceding objects by providing a power tongs having braking means engageable with the stator for opening and closing the jaws, which is another object of the invention.

A further object is to provide a pipe-gripping structure wherein one of the jaws is pivoted directly to the rotor and wherein another jaw, located substantially diametrically opposite the first jaw, is pivoted to a jawcarrying link which, in turn, is pivoted directly to the rotor adjacent the pivotal connection of the first jaw thereto.

Another object is to provide a power tongs wherein the braking means is carried by resilient means mounted on the aforementioned jaw-carrying link.

Another object of the invention is to provide a power tongs which includes stop means for limiting insertion of the pipe into the pipe-gripping structure to properly position the pipe with respect to the jaws. An important object of the invention is to provide an adjustable stop means to permit application of the power tongs to pipes of different diameters.

Another important object is to provide a pipe-gripping structure in which the jaws open automatically if they are worn to such an extent that they cannot grip the pipe securely, thereby preventing scoring of the pipe. Another object of the invention is to provide means 2,703,221 Patented Mar. 1, 1955 ICC carried by the jaws of the pipe-gripping structure for guiding the pipe into position between the jaws during application of the power tongs to the pipe.

Another object of the invention is to provide a power tongs having means for automatically bringing the radial throats in the rotor and stator into registry when it is desired to insert a pipe into the tongs, or to remove it therefrom.

Another object is to provide such a throat-registering means which is adapted to de-energize the power means for the rotor in such a manner that the rotor automatically comes to rest with the radial throat therein in registry with the radial throat in the stator.

An imporant object is to provide such a throat-registering means which is adapted to partially de-energize the power means as the radial throat in the rotor approaches registry with the radial throat in the stator, and which is adapted to subsequently de-energize the power means completely as the radial throat in the rotor registers with the radial throat in the stator.

Still another object is to provide such a throat-registering means which includes control means for varying the rate of delivery of power to the power means, and which includes cam means associated with the rotor and stator for actuating the control means.

As previously indicated, a power tongs of the character under consideration is adapted to be suspended in such a manner that it may be moved laterally into and out of engagement with a vertical pipe, means conventionally being provided to permit inverting the tongs so that the pipe may be rotated in either direction for connection to or disconnection from another pipe. Another object of the invention is to provide an improved suspension mounting which permits the power tongs to be inverted easily, and to provide means for retaining the power tongs in one or the other of its positions.

The foregoing objects of the present invention and the advantages suggested thereby, together with various other objects and advantages which will become apparent, may be attained through the employment of the exemplary embodiment of the invention which is illustrated in the accompanying drawings and which is described in detail hereinafter. Referring to the drawings:

Fig. 1 is a side elevation of a power tongs which em bodies the invention;

Fig. 2 is a plan view of the power tongs with a power means for driving a rotor thereof removed.

Fig. 3 is a fragmentary plan view duplicating the right end of Fig. 2 on an enlarged scale, a portion of the housing of the power tongs being removed;

Figs. 4 and 5 are sectional views respectively taken along the broken lines 4-4 and 5-5 of Fig. 3;

Figs. 6, 7 and 8 are semidiagrammatic plan views illustrating the operation of a pipe-gripping structure of the power tongs;

Fig. 9 is a fragmentary plan view duplicating the left end of Fig. 2 of an enlarged scale;

Fig. 10 is a side elevation of the structure illustrated in Fig. 9; and

Fig. 11 is an end elevation of the power tongs as viewed from the right in Fig. l of the drawings.

Referring particularly to Figs. l and 2 of the drawings, the power tongs ofthe invention includes a housing 20 having an annular portion 21 which is referred to hereinafter as a stator, and having a handle-like arm 22 which extends laterally from the stator. When used in connection with vertical pipes, as in connecting and disconnecting drill string sections, for example, the power tongs is adapted to be suspended in a substantially horizontal position so that it may be swung horizontally into and out of engagement with a pipe to be operated upon. Also, in order that the pipe being operated upon may be rotated in either direction, as in connecting and disbe inverted with respect to the position shown in the drawings. An improved suspension mounting of the invention will be considered in the following paragraph, although it will be understood that other features of the invention are not limited to the particular suspension mounting disclosed herein.

Referring particularly to Fig. ll of the drawings, and also to Figs. l and 2 thereof, the suspension mounting of the invention comprises a bail which is located near the center of gravity of the power tongs for proper balance. The bail 25 comprises a substantially semicircular loop 26 which semi-encircles the housing 20 and includes a pair of arms 27 which are extensions of the loop 26 and which are rigidy connected at their inner ends to the housing. As best shown in Fig. l1 of thc drawings, the arms 27 make acute angles with the loop 26. The suspension mounting includes a grooved roller or pulley 28 which receives the bail 25 to support the power tongs, the pulley being carried by a clevis 29 which may be supported by a cable (not shown) or the like through a swivel fitting 30 (Fig. l). As will be apparent, the power tongs may be rotated readily about a horizontal axis upon application of a turning force thereto. The rotation will be through 180 and will swing the tongs between its upright position and its inverted position whenever a different direction of rotation for a pipe being operated upon is desired. As will be apparent, the pulley 28 engages the hail 25 to support the `power tongs during the entire 180 of rotation between the upright and inverted positions of the tongs, the loop 26 serving as a track for the pulley. In order to retain the power tongs in either its upright position or its inverted position, the bail is provided with notches 31 therein adjacent the intersections of the loop 26 with the arms 27, which notches receive the pulley 28, as best shown in Fig. ll of the drawings.

As previously stated, the bail 25 is located near the center of gravity of the tongs for proper balance. In order to attain stability, the bail is preferably so located that a vertical line through the pulley 28 lies between the center of gravity of the tongs and a pipe being operated on by the tongs. In order to maintain the tongs level under such conditions, a chain 33 is provided at one end with a hook 34 for engagement with an eye 35 on the housing arm 22, the other end of the chain being attached to a suitable supporting structure (not shown) so as to support the housing arm and keep the tongs level.

With such a suspension mounting for the power tongs, it is necessary to provide some means for restraining the housing 20 of the tongs to prevent rotation thereof about the axis of the pipe being operated upon, as is well known in the art. Referring to Figs. 9 and l0 of the drawings, this may be accomplished by attaching one end of a backup line (not shown) to the housing 20 and by attaching the other end of the line to a suitable anchoring structure (not shown), the line preferably being attached to the housing adjacent the outer end of the arm 22 of the housing. In the particular construction illustrated, the back-up line may be attached to a clevis 39 which is pivotally connected to the outer end of the housing arm 22 by a pin 40.

As best shown in Figs. 2 and 1l, the stator portion 21 of the housing 20 is provided with hand grips 38 for use in swinging the power tongs into and out of engagement with a pipe .to be `operated upon and for use in rotating the power tongs between its upright and inverted positions.

The foregoing completes the description of the suspension mounting of the invention and the power tongs per se will now be considered, it being understood that the power tongs per se may be used apart from the specic suspension mounting disclosed Without departing from the spirit of the invention.

In general, the power tongs includes an annular rotor 44 which is disposed with and which is rotatable about the axis of the annular stator 21, the rotor having a radial throat 45 which is registrable with a radial throat 46 in the stator to permit lateral insertion of a pipe into the interior of the rotor, or to permit lateral application of the power tongs vto a pipe when the foregoing suspension mounting is used. The rotor 44 is adapted to be driven by a power means 47 through a transmission 48 and carries a pipe-gripping structure, generally designated by the numeral 49. The pipe-gripping structure 49 includes jaw means comprising relatively movable jaws 50 and 51, and includes actuating means 52 for opening or closing the jaws during rotation of the rotor,

the jaw-actuating means being adapted to open the jaws during rotation of the rotor in one direction and to close the jaws during rotation of the rotor in the opposite direction. The pipe-gripping structure 49 also includes means 53 for guiding a pipe to be operated on into the space between the jaws. In addition to the foregoing general elements, the power tongs includes stop means 54 for limiting insertion of a pipe to be operated on into the annular rotor 44 so as to properly position the pipe relative to the jaws 50 and 51, the stop means being adjustable to accommodate pipes of different sizes, and includes means 55 for automatically bringing the radial throat 45 in the rotor into the registry with the radial throat 46 in the annular stator 21 whenever this is desired. With the foregoing description of the general elements of thc power tongs of the invention in mind, the details thereof will now be considered.

Referring particularly to Figs. l to 5 of the drawings, the annular stator 21 is provided with a peripheral wall 61 having an inwardly extending, lateral or end wall 62 of annular configuration formed integrally therewith. The annular stator also includes a removable lateral or end wall 63 of annular configuration which extends inwardly from the peripheral wall 61 and which is secured thereto by bolts 64, the radial throat 46 being formed in the peripheral wall 61 and the end walls 62 and 63. The annular stator 21 is provided with a Y-shaped portion 65 at one side thereof which is inserted into and suitably secured to a bifurcated portion 66 of the housing arm 22. In the particular construction illustrated, the housing arm 22 is shown opposite the radial throat 46 in the annular stator 21, although it will be understood that the relative positions of the housing arm and the radial throat 46 may be varied without departing from the spirit of the invention.

As best shown in Figs. 3 and 5 of the drawings, the annular rotor 44 is disposed within the annular stator 21 between the end walls 62 and 63 of the latter and is supported by grooved rollers 69 which are carried by bolts 70 extending between the end walls of the stator. The rotor 44 is provided with .an annular rim 71 which extends into the grooves in the rollers 69 and which rests on one of the side walls of each groove so that the rollers support the rotor. As best shown in Fig. 5 of the drawings, peripheral portions of the rotor 44 on opposite sides of the annular rim 71 thereon engage the rollers 69 adjacent the grooves therein to center the rotor with respect to the stator 21. As will be understood, I employ a sufcient number of the rollers 69 to insure that the portions of the annular rotor 44 adjacent the radial throat 45 therein engage and disengage each roller smoothly as the radial throat moves past such roller.

Referring particularly to Fig. 3 of the drawings, the annular rim 71 on the periphery of the rotor 44 is provided with radial teeth forming a gear 76 which is meshed with a pair of driving gears 77, the latter being mounted on shafts 78 carried by the end walls 62 and 63 of the stator 21 and forming part of the transmission 48. The driving gears 77 rotate in the same direction and are spaced apart a distance greater than the width of the radial throat 45 in the rotor 44 so that one of the driving gears is always meshed with the gear 76, irrespective of the position of the radial throat 45 relative to the driving gears.

Considering the remainder of the transmission 48, the driving gears 77 are meshed with a gear 79 which is mounted on a shaft 80 carried by the end walls y62 and 63 of the stator 21. Rigidly connected to the gear 79. as by being formed integrally therewith, is a gear 81. Meshed with the gear 79 is a gear 82 which is rotatably mounted on a power shaft 83 forming part of the power means 47, the power shaft being carried by bearings 54 which are mounted in bearingcaps 85 secured to the end walls 62 and 63 of the stator 21 by bolts 86. Splined or otherwise secured to the power shaft 83 so as to be nonrotatable relative to ,the power shaft but movable axially .thereof is a `gear 89 which is adapted to mesh with the gear 81. The gears 82 and y89 on the power shaft 83 include complementary projections which form a jaw clutch 90 for locking these gears together, thereby locking the gear 82 to the power shaft.

As will be apparent, the gear 81 is larger than the gear 79 and the gear 82 is larger than the gear 89. Consequently, when the axially movable gear 89 is .in a position such that it is meshed with the gear 8l, thc

annular rotor 44 is driven at a relatviely low speed, the gear 82 rotating freely on the power shaft 83 under such conditions. However, when the gear 89 is shifted axially to produce engagement of the jaw clutch 90, it is unmeshed from the gear 81 and connects the power shaft 83 directly to the gear 82. Under such conditions, the annular rotor 44 is driven at a relatively high speed. Thus, the transmission 48 provides two speeds for the annular rotor 44.

In order to shift the gear 89 axially to engage and discharge the jaw clutch 90, I provide an axially movable shaft 91 which carries a yoke 92 for shifting the gear 89 axially upon axial movement of the shaft, the yoke 92 extending into a groove 93 in the hub of the gear 89. In order to retain the axially movable gear 89 in either of its two positions, I provide a spring-pressed detent 94 which is insertable into either of two grooves 95 in the shaft 91.

Referring particularly to Figs. l and 2 of the drawings, the shaft 91 is provided at its outer end with a bifurcated head 98 which receives a cam element 99, the latter being fixed on a shaft 100 having a handle 101 fixed thereon. The shaft 100 is rotatable in brackets 102 carried on the housing arm 22. As will be apparent, rotation of the shaft 100 by means of the handle 101 produces axial movement of the shaft 91 to shift the gear 89 between its two operating positions, the detent 94 serving to releasably retain the gear 89 in either of its operating positions.

As previously indicated, the power shaft 83 forms part of the power means 47, the latter including a stallable rotary air motor 105 in the particular construction illustrated, the stalling torque of the motor limiting the clamping force applied to the pipe. The air motor 105 is shown as secured in a frame 106 by set screws 107, the frame 106 having arms 108 which are bolted or otherwise secured to the housing arm 22. As best shown in Fig. 1 of the drawings, the air motor 105 may be supplied with air through a line 109, a manually operable valve 110 being interposed between the line and the motor. The air motor 105 is reversible, its direction of rotation being controllable by a lever 111.

Considering the pipe-gripping structure 49 of the power tongs with particular reference to Figs. 3 and 5 of the drawings, projecting inwardly from the inner periphery of the annular rotor 44 is a jaw-carrying element 115, the latter being shown as formed integrally with the' rotor although it will be understood that it may be formed as a separate element which may be suitably secured to the rotor. As best shown in Fig. 5 of the drawings, the jaw 50 is pivotally connected to the jaw-carrying element 115 for rotation about an axis which is spaced from and parallel to the operating axis of the power tongs, i. e., the axis of rotation of the annular rotor 44, the pivotal connection between the jaw 50 and the element 115 being provided by a pin 116. This pin extends through interleaved fingers on the jaw 50 and the element 115 and is provided with a head 117 at one end, therein being threaded at its other end into one end of a link 118 the function of which will be discussed hereinafter. The pin 116 carries a spring washer 119 for imposing frictional restraint on the jaw 50 so as to keep this jaw from pivoting freely.

As best shown in Fig. 3 of the drawings, an arcuate jaw-carrying link 120 is pivotally connected at one end to the jaw-carrying element 115 by means of a pin 121, this pin being located adjacent and parallel to the pin 116 for the jaw 50. The jaw-carrying link 120 extends across the annular rotor 44 and is supported adjacent its opposite end by a bearing element 122 which is movable in an annular recess 123 in the inner periphery of the rotor, as best shown in Fig. 5 of the drawings. As will be understood, the bearing element 122 is carried by the jawcarrying link 120.

The jaw 51 is located substantially diametrically opposite the jaw 50 and is pivotally connected to the jawcarrying link 120 by a pin 124 which extends through interleaved fingers on the jaw 51 and the link 120, this pin being substantially diametrically opposite the pin 116 connecting the jaw 50 to the jaw-carrying element 115 and the pin 121 connection the jaw-carrying link to the element 115. As best shown in Fig. 5 of the drawings, the pin 124 for the jaw 51 is provided with a head 125 at one end and is threaded at its other end into a link 126 the function of `which will be discussed hereinafter, the

link 126 being pivotally connected to the aforementioned' link 118 at 127, as shown in Fig. 2 of the drawings. The pin 124 carries a spring washer 128 for imposing frictional restraint on the jaw 51 to prevent free pivoting of this jaw.

As best shown in Fig. 3 of the drawings, the jaws 50 and 51 are provided with concave inner surfaces which face each other and which co-operate to deline a pipereceiving space 131 therebetween. The jaws 50 and 51 are prererably provided with pipe-gripping elements 132 which extend inwardly into the pipe-receiving space 131 and which are adapted to engage a pipe in the space 131. As shown, the pipe-gripping elements 132 are preferably serrated so that they will provide a positive grip on the pipe.

l'he jaw-actuating means 52 comprises braking means 135 for opening and closing the jaws 50 and 51, i. e., for producing relative movement of the jaws 50 and 51 respectively away from and toward each other, in response to rotation of the annular rotor 44 relative to the annular stator 21, 'such braking means being adapted to open the jaws in response to rotation of the rotor in one direction and to close the jaws and initiate their pipe-clamping action in response to rotation of the rotor in the opposite direction. As best shown in Figs. 3 and 5 of the drawings, the braking means 135 includes a braking element which comprises a pair of arcuate brake shoes 136 respectively disposed on opposite sides of the annular rotor 44 and adapted to frictionally engage the inner peripheries of the end Walls 62 and 63 of the annular stator 21. As indicated in Fig. 3, the brake shoes 136 are interconnected by a web 13'/ so that they operate as a unit. Referring to Fig. 5 of the drawings, tne brake shoes 136 are provided with surfaces 138 respectively bearing against but slidable relative to the ends of the annular rotor 44 so that the rotor positively supports the brake shoes.

Continuing to refer to Figs. 3 and 5 of the drawings, the brake shoes 136 are operatively connected to the jaw-carrying link 120 and are biased radially outwardly into frictional engagement with the stator 21 by irregular leaf springs 141. 'iwo such springs are employed, one disposed on one side of the jaw-carrying link and engaging one of the brake shoes 136 and the other disposed on the opposite side of the jaw-carrying link and engaging the other brake shoe. As best shown in Fig. 3 of the drawings, each of the springs 141 is connected at one end to a supporting block 142 by a screw 143, the supporting blocks being pivotally connected to the jawcarrying link 120 at 144. As will be apparent, this construction permits the springs 141 to pivot relative to the jaw-carrying link 120, the extent of such pivotal movement being limited by stop pins 145 and 146 carried by the jaw-carrying link and respectively disposed on opposite sides of each spring 141. The opposite ends of the springs 141 engage the brake shoes 136 by being inserted into notches 147 therein.

As best shown in Fig. 3 of the drawings, the guide means 53 comprises a pair of Wing-like guides 150, one of these guides being carried by the jaw 50 and extending generally toward the radial throat 45 in the rotor 44 and the other being carried by the jaw 51 and also extending generally toward the radial throat 45. As indicated in big. 6 of the drawings, the guides 150 are adapted to guide a pipe 151 to be operated upon into the pipe-receiving space 131 between the jaws so as to keep the pipe from entering the spaces behind the jaws, i'. e., between the jaws and the inner periphery of the rotor 44.

Referring now to Fig. 2 of the drawings, the pipe-stop means 54 includes a pipe-stop element 152 which is rotatably mounted on the previously mentioned link 118 by means of a pin 153. The pipe-stop element 152 is provided with a plurality of notches 154 any one of which may be directed toward the pipe-receiving space 131 between the jaws 50 and 51 by rotating the pipe- It will also be assumed that the radial throats 45 :and 46 in `the rotor and lthe 4stator l21 are in registry, 1as shown in Fig. 6 of the drawings. Under such conditions, the pipe 151 may be inserted into the pipe-receiving space 131 between -the jaws 50 4and 51, the pipe being guided into such space by the guides 150. As will be understood, the pipe 151 .may be inserted into the pipe-.receiving space 131 by moving the pipe laterally relative to the power tongs, or by moving the power tongs laterally 4relative to the pipe.

As the pipe 151 engages the jaws .50 and '51, lit rotates the jaws into their closed position, as indicated in Fig. 7 of the drawings, movement of the jaws beyond their closed position being limited by engagement of the pipe with the pipe-stop element 152. When 'the jaws 50 and 51 are closed, the center of the pipe-receiving space 131, and, consequently, the center of the pipe 151, preferably lie exactly on, or slightly to the left of, a line normal to and intersecting the axes of the pivot pins 116 and 124 for the jaws. Under such conditions, engagement of the pipe 151 with the vpipe-stop element 152 lprevents opening movement of the jaws 50 and 51 toward the left, as v-iewed .in Fig. 7 of the drawings. Opening movement of the jaws 50 .and 51 toward the right, as viewed in Fig. 7 of the drawings, `is prevented under such conditions because of the fact that the toggle mechanism provided by the jaws 50 and 51 would have to move past dead center, i. e., the center of the pipe-receiving space 1.31 would have to move to the right of the line connecting the axes of the pivot pins 116 and 124, to permit this.

With the jaws 50 and 51 closed upon the pipe 151, the operator of the power tongs opens the valve 110 controlling the rate of delivery of air to the air motor 105, the reversing lever 111 of the air motor being set in such a position that the air motor, acting through the transmission 48, .rotates the annular rotor 44 in the direction indicated by the arrows 155 in Figs. 7 and 8. Either the high or low speed of the transmission 48 may be selected, depending upon the anticipated load. Normally. the rotor 44 will be driven at the higher speed provided by the transmission in initially threading the pipe 151 into a coupling (not shown), for example, and the lower speed will be employed to tighten the pipe, as is well known in the art. Similarly, in loosening the pipe 151 from a coupling, or the like, the lower speed of the rotor will be used, the higher speed being employed once the pipe `has been loosened, as is well `known in the art.

Referring again to Fig. 7 of the drawings. as the rotor 44 begins to rotate relative to the stator 21 in the direction of the arrow 155, the brake shoes 136 remain stationary and act through the springs 141 and pins 146 to 4pivot the jaw-carrying link 120 about the axis of the pin 121 in the counterclockwise direction relative to the rotor. Such pivotal movement of the jaw-carrying link 120 relative to the rotor 44 disolaces the jaw 51 inwardly toward the jaw 50 so Vthat the pipe 151 is securely clamped between the two iaws. Due to the self-energizing 'action of the pipe-gripping structure, the clamping force applied to the lpipe increases as the torque applied to the rotor 44 increases until such time as the air motor 105 stalls Ito .impose an `upper limit on the clamping force which can be applied to the pipe. As indicated in Fig. 8 of the drawings, the brake shoes 136 thereafter rotate with the `1'otorf44.

It 'will be noted that, as shown in Figs. 7 and 8, the springs 141 bear against the stop pins 146 during rotation of the rotor 44 in the direction of the arrows 155, the stop pins 146 thus serving as fulcrums for the sprin as.

As indicated previously, an important feature of the invention is that the iaws 50 and 51 open automaticallv to release the pipe l151 if the pipe-gripping elements 132 are worn to such an extent :that they are incapable of gripping the pipe properly, thereby preventingy scoring of the pipe. In order to consider how this effect is attained, it is first necessary to consider the forces ap plied to the pipe bythe jaws 50 and 51. Referring to Fig. 8 of the drawings, when the jaws 50 and 51 are closed on the pipe 151, the jaw 51 applies to the pipe a force 157 which acts along a line intersecting and normal to the axes of the pins 121 and 124 in a direction toward the pin 121, the .force 157 thus being applied to the pipe at an acute angle, i. e.. being intermediate a normal force and 1a tangential force. Conversely, the jaw 50 applies to the :pipe a force 158 which is equal .and opposite to the force 157 and which acts along a parallel line intersecting and normal to the axis of the pin 116, the force 158 thus being applied to the pipe at an acute angle also. -As long as the jaws 50 and 51 are not yworn excessively so that an adequate coeicient vof friction, e. g., of the order of magnitude of 0.30 to 0.40, obtains between the jaws and the pipe, no slippage can Aoccur so that the forces 157 and 158 are equal with the result that the jaws remain closed on the pipe. However, if either of the jaws is worn excessively so that slippage can occur, the forces 157 and 158 become unequal with the result that the jaws open to release the pipe. Thus, scoring of the pipe is prevented.

Whenever it is desired to release the pipe 15-1, the jaws 50 and 51 may be opened readily by reversing the direction of the rotation of the rotor 44, this .being accomplished by changing the setting of the reversing lever 111 controlling the direction of rotation of the air motor 105. Upon reversal of the direction of rotation of the rotor, the brake shoes 136 again tend to remain stationary so as to rotate the jaw-carrying link in the clockwise direction, as viewed in Figs. 6 to 8 of the drawings, relative to the rotor so as to move the jaw .S1 away `from the jaw 50, thereby opening the jaws to release the pipe. Subsequently, the pipe may be removed through the radial throats 45 and 46 in the rotor 44 and stator 21. The manner in which the radial throat 45 in the rotor is brought into registry with the radial throat 46 in the stator by the throat-registering means 55 will be considered in detail hereinafter.

It will be noted that, in Figs. 6 to 8 of the drawings, I have illustrated the operation -of the pipe-gripping structure 49 of the power tongs when the latter is used to rotate the pipe 151 in the clockwise direction. However, if rotation of the pipe `in the counterclockwise direction is desired, this may be attained by inverting the power tongs in the manner hereinbefore described. The operation of the pipe-gripping structure 49 when the power tongs is inverted is identical to the operation thereof with the power tongs upright.

Considering the throat-registering means 55, in view of the fact that the annular rotor 44 lmust ybe rotated in the reverse direction, i. e., in the counterclockwise direction as viewed in the drawings, in order to open the jaws 50 and 51 to release a pipe held thereby, the throatregistering means is designed to operate to bring the radial throats 45 and 46 in the rotor and stator into registry only during reverse rotation of the rotor. However, it will be understood that the throat-registering means 55 may operate during rotation of the rotor 44 in either direction without departing from the spirit of the invention. The throat-registering means will now be considered in detail with reference to Figs. 3, 9 and l0 of the drawings.

As best shown in Fig. 3 of the drawings, the throatregistering means 55 includes cam means comprising a cam element carried by the rotor 44. This cam element has a first rise 161 and a second rise 162, the two rises being connected by a dwell 163. The cam means also includes a cam follower element 164 which, during reverse rotation of the rotor 44, i. e., during rotation of the rotor in the direction indicated by the arrows 165 in Figs. 3 and 9 of the drawings, engages the first rise 161 of the cam element 160, the dwell 163 thereof and the second rise 162 thereof in that order. The cam follower element 164 is pivotally connected to the stator 21 by a pin 166.

The cam follower element 164 is provided with an arm to which is connected one end of a cable 170, the opposite end of the cable being connected to a plunger 171 which is reeiprocable in bearings 172 carried by the housing arm 22. The cable is disposed in a sheath 173 which is suitably secured to the housing 20.

As will be apparent, when the cam element 160 engages the cam follower element 164 during rotation of the rotor 44 in the direction of the arrows 165, the cam follower eiement is rotated in the clockwise direction, as viewed in Figs. 3 and 9 of the drawings, so that the cable 170 moves the plunger 171 to the right. The plunger 171 is manually movable to the left, as viewed in Figs. 9 and l0 of the drawings, by means of a handle 174 having a yoke 175 which is pivotally connected to the plunger at 176. The yoke 175 is pivotally mount ed by disposing a projection 177 Ithereon in an opening in a bracket 178 carried by the housing ann 22.

The plunger 171 carries a cam element 183 having a first rise 184 which corresponds to the rst rise 161 of the cam element 160, a second rise 185 which corresponds to the second rise 162 of the cam element 160, and a dwell 186 which corresponds to the dwell 163 of the cam element 160. The rst and second rises 184 and 185 are formed by conical surfaces on the cam element 183 and the dwell 186 is formed by a cylindrical surface thereon. The cam element 183 includes another cylindrical surface providing a second dwell 187.

The throat-registering means 55 also includes control means comprising, as best shown in Fig. 10 of the drawings, a control valve 190 which is connected in parallel with the valve 110 so that air to operate the motor 105 may ow to the motor through either valve, as will be discussed in more detail hereinafter. The control valve 190 is rigidly connected to brackets 191 by bolts 192 and the brackets 191 are pivotally connected to one of the bearings 172 for the plunger 171 bya pin 193 so that the control valve may rotate toward and away from the cam element 183 on the plunger 171. The control valve 190 is biased away from the cam element 183, i. e., is biased in the clockwise direction as viewed in Fig. 10 of the drawings, by rat trap springs 194. The force applied to the control valve 190 by the springs 194 is op* posed by a bolt 195 having a wing nut 196 thereon, the bolt being pivotally connected to the control valve at 197. As will be apparent, the position of the control valve 190 relative to the cam element 183 may be varied by means of the wing nut 196, the wing nut and the bolt 195 serving as an adjusting means for the throat-registering means 55 as will be discussed in more detail hereinafter.

The control valve 190 is provided with a stem 200 which, when moved upwardly as viewed in Fig. 10 of the drawings, opens the control valve to permit flow of air therethrough to the motor 105. Conversely, when the stem 200 is in its lowermost position, as shown in Fig. l of the drawings, the control valve 190 is closed. The stem 200 is actuable by a cam follower element 201 which is pivotally connected to the control valve at 197 and which is adapted to engage the cam element 183 to actuate the stem 200. When the plunger 171 is in a position such that the cam follower element 201 is in engagement with the dwell 187, the cam follower element holds the stem 200 in its uppermost position so that the control valve 190 is fully open. If the cam element 183 is moved to the right, as viewed in Fig. l0 of the drawings, so that the cam follower element 201 engages rst the rise 184 of the cam element and then the dwell 186 thereof, the cam follower element permits the stem 200 to move to an intermediate position so that the control valve is only partially open. Further movement of the cam element 183 to the right results in engagement of the cam follower element 201 with the rise 185 of the cam element to permit the stem 200 to move into its lowermost position wherein, as previously mentioned, the control valve 190 is closed. The extent to which the control valve 190 is open when the cam follower element 201 engages the dwell 186 is determined by the setting of the wing nut 196, As will be apparent, if the wing nut 196 is adjusted to permit the control valve 190 to move away from or toward the cam element 183, the extent to which the control valve is open when the cam follower element 201 is in engagement with the dwell 186 is increased or decreased. This permits varying the partially de-energized speed of the air motor 105 and thus permits varying the distance the rotor 44 will coast when the control valve closes to completely deenergize the motor. As will be discussed in more detail hereinafter, by suitably adjusting the wing nut 196, the rotor 44 can be caused to stop with the radial throat 45 therein precisely in registry with the radial throat 46 in the stator 21.

Considering the operation of the throat-registering means 55, the plunger 171 is normally in a position such that the control valve 190 is closed. In other words, the position of the plunger 171 is normally such that the cam follower element 201 engages the rise 185 of the cam element 183, which permits the control valve to close. Thus, under such conditions, the rate of delivery of air to the motor 105 is controlled solely by the valve 110.

Whenever the operator desires to stop the rotor 44 with the radial throat 45 therein in registry with the radial throat 46 in the stator 21 so as to permit insertion or removal o f a pipe, the operator rst sets the reversing lever 111 in a position such that the rotor is driven in the counterclockwise direction, as viewed in the drawings. As previously explained, this is the direction of rotation of the rotor 44 for opening the jaws 50 and 51. Subsequently, the operator closes the valve and, by means of the handle 174, moves the plunger 171 and the cam element 183 all the way to the left, as viewed in the drawings, so that the cam element 183, acting through the cam follower element 201 fully opens the control valve 190. Thus, this transfers control of the rate of delivery of air to the motor 105 from the valve 110 to the control valve 190.

Subsequent to the foregoing operations, the cam element carried by the rotor 44 approaches the cam follower element 164. As the cam follower element 164 engages the rise 161 of the cam element 160, it acts through the cable to move the plunger 171 and the cam element 183 toward the right, as viewed in the drawings, so that the cam follower element 201 disengagcs the dwell 187 and engages the rise 184. The cam and cam follower elements 160, 164, 183 and 201 are so designed that: when the cam follower element 164 is in engagement with the rise 161 of the cam element 160, the cam follower element 201 is in engagement with the rise 184 of the cam element 183; when the cam follower element 164 is in engagement with the dwell 163 of the cam element 160, the cam follower element 201 is in engagement with the dwell 186 of the cam element 183; etc. Thus, by the time that the cam follower element 164 engages the dwell 163 of the cam element 160, the control valve 190 is only partially open so that the motor 105 is partially de-energized, i. e., the rate of delivery of air is reduced, This results in a decreased speed for the rotor 44 as the radial throat 45 therein approaches registry with the radial throat 46 in the stator 21.

With the rotor 44 thus rotating at a relatively low speed, the cam follower element 164 engages the second rise 162 of the cam element 160 to cause the cam follower element 201 to engage the second rise of the cam element 183. The second rise 162 of the cam element 160 is so positioned relative to the radial throat 45 in the rotor 44 that the cam element 183, acting through the cam follower element 201, closes the control valve just before the radial throat 45 registers with the radial throat 46 in the stator 21. Thus, with the structure described, the motor 105 is partially de-energized as the radial throat 45 approaches registry with the radial throat 46 and is completely de-energized when the two radial throats are in registry.

As previously discussed, by adjusting the wing nut 196 so as to move the control valve 190 toward or away from the cam element 193, the extent to which the rotor 44 coasts after closure of the control valve can be varied to insure that the radial throat 45 is precisely in registry with the radial throat 46 when the rotor 44 comes to a stop. Thus, corrections for coasting of the rotor 44, or for other factors, may be made.

Thus, the throat-registering means 55 automatically stops the rotor 44 with the radial throat 45 therein precisely in registry with the radial throat 46 in the stator 21. As will be apparent, by first partially deenergizing the motor 105 so that the rotor is decelerated to a relatively low speed, and by subsequently completely de-energizing the motor so as to minimize coasting of the rotor, very accurate registry of the two throats may be attained.

Although I have disclosed an exemplary embodiment of my invention for purposes of illustration, it will be understood that various changes, modifications and substitutions may be incorporated in the embodiment disclosed without departing from the spirit of the invention.

I claim as my invention:

l. In a pipe tongs, the combination of: a generally annular stator; a generally annular rotor carried by said stator and rotatable about the axis of said stator; a link; opposed jaws disposed within said rotor and defining a pipe-receiving space therebetween for receiving a pipe from one side thereof, one of said jaws being pivotally connected to said rotor, the other of said jaws being pivotally connected to one end of said link which is pivotally connected at its other end to said rotor adjacent said one jaw, said link having a laterally offset intermediate portion arranged to extend across said rotor clear of said pipe-receiving space on the side thereof opposite said one side; means operatively connected to said link for pivoting said` link relative to said rotor to open and Al1 close-said .-jaws; mounting means `carried thy-said rotor; .stop ymeans .on saidmountingmeans,fsaidstop means being .located adjacent said '-pipereceivingfspacefon th'e sid'e thereof oppositeisaid one-isidelforgpositioninga pipe between said jaws; and meansfor-rotatinglsaid rotor.

,2. ,'In a power tongs, .the :combination of: ian annular stator; an annular rotor .disposed 'within -and rotatable about .the axis of .said.stator; :a .link-lhavingfits vends 1respectively located on opposite .sides of the center -of said rotor; rst pivot .means "connecting one 'end of said link .to `said rotor and 'providing an :axis parallel -to said stator axis; jaw means disposed within said rotor and including a pair .of jaws ,providing a pipe-receiving space therebetween; second 'pivot means .adjacent said first pivot vmeans connecting one 'of `said jaws -to said rotor, said .second `pivot means .providingtan axis parallel to said stator axis; third .pivot .means substantially diametrically opposite 4said first 'and second pivot means connecting the other .of said jaws fto lthe opposite lend of said link,.said link carrying said other jaw, said third pivot means providing an .axis -parallel to 'said stator axis and without .a plane .containing 'the axes provided bysaid iirst and second .pivot means; jaw-actuatingfmeans operatively connected to vsaid jaw-carrying link and operable upon rotation .of said rotor relative to said stator .for pivoting said jaw-carrying link relative to said rotor so as to open vand-close said jaws; and power means operatively connected .to .said `rotor and carried by said stator for rotating said rotor.

3. A power tongs as set forth in lclaim 2 wherein said rotor and said stator are provided with registrable radial throats for lateral insertion of a pipe into said rotor and into said pipe-receiving space.

4. Apower tongs asset forth in claim 3 wherein said jaw-actuating means comprises braking means connected to said jaw-carrying link and engageable with said stator.

5. A power tongs according to claim 4 including resilient means for connecting said braking means to said jaw-carrying link.

6. In a power tongs, the combination of: an annular stator having a radial throat therethrough for lateral insertion of a pipe thereinto; an annular rotor carried by and rotatable about the axis of lsaid stator, `said rotor having a radial throat therethrough which is registrable with .said radial throat in said stator for lateral insertion of the pipe through said radial throats into said rotor; a pipe-gripping structure carried by said rotor for engaging vthe pipe to rotate same during rotation of said rotor; energizable and de-energizable power means `for rotating said rotor; and control means operatively connected to said power means and engageable 'by an 'element of said rotor for first partially de-energizing said power means as said 'radial throat in said rotor approaches registry with said radial throat in said stator to continue to rotate said rotor at reduced speed, said control means being operable by a further element 'of 'said rotor upon continued rotation of said rotorpto completely de-energize said power means as said radial throat in said rotor registers with said radial throat Vin said stator.

7. A powertongs as set forth in claim l6 wherein said control 4means includes `power control means for regulatingthe rate'of delivery of power to vvsaid power means, wherein said control means is a cam follower element carried by said stator and operatively connected to said power control means, and wherein said` elements .on said vrotor comprise cam elements carried by said rotor for .actuating said cam follower element.

8. A power tongs as set forth in claim 7 wherein said cam element lis provided with a cam surface comprising .two rises interconnected by a dwell, one of said rises actuating said cam follower `element to cause said control means to partially de-energize said power means, the other of said rises actuating said cam follower element to cause said control means to completely de-energize said power means, and said dwell actuating said cam follower element to 'cause said control means to mainain said power means in partially de-en'ergized conmon.

:9. A power tongs according to claim 8 wherein said power means includes an air motor kand wherein said control ymeans includes a control valve for regulating the rate of delivery of air to said motor.

10. In a pipe tongs, the icombination of: 'an annular stator; an annular rotor 'carried `by and rotatable `about the .axis of said stator; a pipe-grippinglstructure 'carried fing 'without aplane vcontaining'the axes of said'rst'and byifsaidrotor and comprising a pairjof'spaced jaws 'which provide fa pipe-receiving space adapted to receive a pipe 'therebetween ifrom vone side thereof; 'stop 'means carried by said pipe-gripping structure "closely A'adjacent vsaid pipe-receiving *space at a position intermediate said 'jaws at the other wside thereof and `engageable jby a pipe -in said pipe-receiving Aspace `for l'positioning the pipe relative to said -'jaws; and 'means 4for'rotating said rotor.

11. A'pipe'tongs'as setfforth in claim l0wherein s aid 'stop means is movably 'mounted ron "said pipe-'gripping structure whereby -it is adjustable to properly vposition pipes of diierent diameters.

l12. In a power tongs, the'combination of: an annular stator; an annular rotor carried by and rotatable about the axis'of vsaid stator; a link having its ends respectively located on opposite `sides of the center of 'said irotor; irst pivot means connecting'oneend'of saidlink'to said rotor; jaw means disposed `within said rotor and including a pair of-jaws providingapipe-receiving space therebetween; second pivot means adjacent said iirst lpivot means and Aconnecting one of said jaws to said rotor; third pivot -means substantially diametrically 'opposite said first and lsecond pivot 'means VAand connecting the other of said vjaws to the Vopposite end of said'link,said lin-kcarrying -said otherjaw, the axis of said third pivot means being without aplane containing the axes of said first and -second pivotrneans; jaw-actuating means operatively connected to said jaw-carrying link for openingand closing said jaws; 'link means'connectedat one end to said second pivot means and at its'otherendto saidthird pivot means; lstop means carried by said link means and engageable by a pipe in said pipe-receiving space =for positioning the pipe relative to said jaws;and power means operatively connected vto said rotor and carried by said lstatorfor rotating said rotor.

y13. A power 'tongs according to claim 12 wherein said-stop means is rotatable relative to said link 'means to accommodate pipes of different diameters.

14. In pipe tongs, the combination of: an annular stator providing a radial 'throat 'for lateral insertion of a pipe thereinto; an annular rotor carried by'and rotatabl'eabout the axis of said stator and providing aradial throat which Ais registrable with said radial throat `in said statorfor lateral insertion otthe pipe through said radial throats intosaid rotor; a pipe-gripping structure carried by and disposed within 'saidsi'roton said pipegripping structure including a pair of`jaws 'which provide a pipe-receiving space therebetween fora pipe inserted into said rotor through said radial throats, 'said pipe-gripping structure further including guide means carried by said jaws for 'guiding the pipe into said pipereceiving space between said jaws during lateral insertionof the pipe into said rotor through said radial throats, said vguide means providing a pipe-entry Vpassage 'which is ysubstantially the :same width as said radialthroat in said rotor when said jaws are open to receive a pipe; and means forl rotating ysaid rotor.

l5. A pipe tongs as set forth in claim 14 wherein said guidemeans comprises a'par of guides respectively carried by said jaws Vand extending generally in the direction of said radial throat in said rotor.

16. In `a suspension 'mounting for 'a pipe tongs, the combination of: a substantially semicircular bail semiencircling said pipe tongs, said bail'including a 'substantially semicircular'loop which terminates 'at its ends in generally radial arms connected to said pipe tongs, said arms making acute angles with said loop; suspension means; fand a pulley'carried by said suspension means and engaging said bail.

174A suspension mounting as sei forth in claim 16 wherein said 'bail is provided with notches for said pulley respectively adjacent the intersections of said loop and said ".arms.

18. In a Vpipe Jtongs, the combination of: a rotor rotatable about the axis ofthe pipe; a link; first pivot means connecting one end of said link to 'said rotor; jaw means including a 'pair-of jaws 'providing a pipereceiving space therebetween; second` pivot means adjaycent said first pivot means for connecting one of 'said jaws tosaid rotor; third pivot 'means substantially 'diametrically 'opposite said first andv second 'pivot 'means for connecting the other of 'said jaws to Vthe opposite end of s'aidlink, 4the axis of said'third pivot meansbesecond pivot means; and jaw-actuating means operatively 1,831,259 Peterson et a1 Nov. 10, 1931 connected to said link for pivoting said link relative to 2,550,040 De Hetre Apr. 24, 1951 said rotor so as to open and close said jaws. 2,618,468 Lundeen Nov .18, 1952 References Cited in the le of this patent 5 UNITED STATES PATENTS 1,300,995 Moody Apr. 15, 1919 

